Automatic radio control system



Nov. 6, 1956J J. 1. HAGOPIAN ETA'. 2,769,601

AUTOMATTC RADIO CONTROL SYSTEM Filed Aug. 18, 1950 7 Sheets-Sheet l 9 t6 [5 40km/cg mean-e f) ff Nov. 6, 1956 J. J. HAGOPIAN ET AL 2,769,601

AUTOMATIC RADIO CONTROL. SYSTEM Filed Aug. 18, 1950 7 Sheets-Sheet 2 81M: eFf l I www FLAPr-l l Nov. 6, 1956 J. J. HAGOPIAN ETAL 2,769,601

AUTOMATIC RADIO CONTROL SYSTEM Filed Aug. 18. 195,0 7 Sheets-Sheet 3 Nov. 6, 1956 J. J. HAGOPIAN x-:T.-^`

AUTOMATIC RADIO CONTROL SYSTEM 7 Sheets-Sheet 4 Filed Aug. 18, 1950 BWI NML

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N0V 6, 1955 J. J. HAGOPIAN ETAT. 2,769,601

AUTOMATIC. RADIO CONTROL SYSTEM Filed Aug. 18, 195o 7 Sheets-Sheet 5 ik I Nov. 6, 1956 J. J. HAGOPIAN ETAL AUTOMATIC RADIO CONTROL SYSTEM 7 Sheets-Sheet 6 Filed Aug. 18, 1950 0. .i 666mm OIV oFF

Nov. 6, 1956 .1.J. HAGOPIAN ETAL 2,769,601

AUTOMATIC RADIO CONTROL SYSTEM Filed Aug. 18, 195.0

'7 Sheets-Sheet 7 N N 'n v n \s A v0 m Maza om off-5v THE/a. Paravr Afro/Mfr United States 2,769,601 AU'roMATIC RADIo CONTROL SYSTEM Application August 18, 1950, Serial No. 1S0,36'7 Claims. (Cl. 244-14) This invention relates to remote control systems, and more particularly to improvements in the means and method of controlling a drone aircraft through a remote radio control system.

Various remote aircraft control systems at present use an electrical automatic pilot to which signals are fed by means of transmitted radio waves having predetermined modulation frequencies respectively assigned to operate various control circuits in a receiver, these control circuits being connected to corresponding autopilot signal input circuits for the desired response of the aircraft attitude. Other func-tions besides changes in flight attitude of the controlled craft are similarly effected, such as lowering and raising of landing gear and turning on and off automatic altitude control, for example.

In such systems where a given modulation channel is assigned for each separate function, the number of control functions, and, hence, the completeness of the control is limited by the number of available channels. The maximum number of channels is in turn limited by other factors, such as the frequency spread of the filter circuits and of the entire R. F. circuit components in the receiver,

`and size and weight limitations governing the number of lter circuits, for example. Therefore, the remote control of many aircraft auxiliary or emergency functions is not possible unless other means are devised.

It is an object of the present invention to provide a remote radio control system of the general type as discussed above, for an aircraft, guided missile, or the like, wherein more functions of control can be performed than the number of modulation channels provided.

Certain other known control systems provide a variety of remotely controlled functions from relatively few control channels by means of a multiple-position selector switch, which is moved one position each time a stepping switch is operated, to connect in readiness a particular control circuit, the latter being then changed as desired through -a master operating switch connected in another channel to activate whatever circuit is set up at the selector switch. Some disadvantages of this type of control system are the number of separate operations required for effecting any particular control function, the relatively long time thus consumed, the inability to perform a plurality of certain functions simultaneously, and the resulting large number of errors which it is possible for the remote operator to make.

For these reasons, further objects of this invention are to provide a remote radio control system having a greater number of operative control circuits than the number of modulation channels available, in which any control function can be controlled with but a single control member, in which any function is in readiness for operation substantially instantly after the previous operation, and in which only those functions that can be correctly performed are possible for the remote operator -to make `at any time.

A further object is to provide an improved means which will achieve remote aircraft control from the instant immediately following launching through nal landing operal. atetu:

2,769,601 ce lratented Nov. l6,' 1,956

tions, including means for automatically operating em'ergency control functions in the event of loss of the remote control signal power.

Other objects and features of advantage will be noted in the detail description of specific apparatus to follow, but this invention is not deemed to be limited to the specific apparatus disclosed herein, since various forms or modifications may be adopted.

Briefly, our invention comprises a pulse-operated radio control link system including a plurality of coded signal channels, one or more of which is connected to operate transfer means for switching the outputs of the remaining channels from one set of respective functional control circuits to an additional set. This duplexing means is accompanied by suitable time delays for automatic energizing and de-energizing of relay circuits so that after a certain remote control member is moved to require operation of the transfer means, the signal pulse in the proper channel is sent and then the transfer means is reset to a steady state position to allow proper operation of other remote control members not requiring use of the transfer means. In this manner, for example, a total of 2(x-l) control circuits can be selectively energized by the use of x control channels when one of those channels operates to provide duplexing of the remainder. The pulse signals received in the controlled craft are converted, by suitable relays, into various completed electrical circuits conventionally designed to produce the desired operation.

In the event of failure of the transmitted carrier wave to maintain a predetermined level at the controlled craft, or a failure in the receiver, an emergency relay is caused to substitute certain fixed control circuits therein in place of the normal remote control circuits, provisions being made for precluding operation of this emergency relay until suicient time has elapsed after launching for the craft to reach a safe altitude. Remote control member locking means is preferably provided to lock certain of these members against movement by the operator when a transmitting circuit normally operated by a member is temporarily disrupted by the aforementioned transfer means. Connecting the transfer means to automatically transmit a transfer signal substantially simultaneously with a pulse signal in a normal channel, when required, results in requiring only one control member for any desired function.

Our invention will be more clearly understood by reference to the accompanying drawings of a preferred embodiment thereof, in which:

Figure 1 is a perspective View of an aircraft under control from a remote ground station, showing in block form the transmitting and airborne equipment of the present invention.

Figure 2 is a schematic diagram, partly in block form, showing the general outline of the transmitting station equipment used in the system of Figure 1.

Figure 3 is a schematic diagram, partly in block form, showing the general outline of receiving and selecting equipment mounted in the radio controlled craft of Figure l, this equipment taking signals directly from the apparatus in Figure 2.

Figure 4 is a schematic diagram, partly in block form, showing a control unit directly connected to the apparatus in Figure 3 as indicated by correspondingly lettered output and input leads.

Figure 5 is a schematic wiring diagram of the transmitter controller unit of Figure 2.

Figure 6 is a schematic wiring diagram of the transmitter relay unit of Figure 2, this unit being directly connected to the apparatus in Figure 5 as indicated by correspondingly lettered output and input leads.

Figure 7 is a partial structuralview of the controller unit showing the arrangement of solenoid-operated means www for locking the control knobs on the transmitter controller unit. Y

Figure 8 is an elevation view of the aircraft in position on a launching device, showing in schematic form a circuit means for energizing -a time. delay relay lin the craft at the same time a`s' starting 'the launching device.

Figure 9 is a diagram showing the vtime relationship of ILS-volt pulses used in an alternatefunction tran'sfer 'Aem- .bodimentof the present invention.

Figure .l is a schematic wiring diagram showing a portion of a modified 'transmitter controller unit and relay unit as used in the alternate embodiment. Y

4Referring `first to Figure `l .for an overall description of this'systeni, an laircraft 1 is 'operated lby a control system comprising a transmitting'station 2,`on the ground or' in another aircraft, and airborne equipment including a receiver a'nd selector unit 3, receiver output adapter 4, and control .unitSjand all actuated equipment controlled thereby is represented by the dotted box'6. This -actuated equipment, "for the specific apparatus disclosed herein, includes pitch control surfaces, bank control surfaces, throttle, automatic altitude system, automatic heading system, landing gear, landing flap surfaces, and a smoke signal apparatus. These functions will be described later insofar 'as they have a bearing on the present invention.

At the transmitting station 2, as shown in Figure 2, is located a'transm-itter 7, a transmitter controller unit 9, and a transmitter relay unit 10.- The controller unit 9 contains a` manuallyopefated throttle control knobl 11, pitch vcontrol knob 12, and bank control knob 14. At# tached to be rotated by`each respective control knob is a star wheel arranged tordeflect'a switch toggle 16 in one of two directions'and then let` the toggle" return to neutral when thestar wheel is rotated one notch in one direction. Opposite toggle deflection results from opposite star wheel' rotation, and two`spring`loadedV control switches 17 are mounted tobe respectively 'actuated on and off by heels 19 of the toggle 16 during deflection thereof. i

In addition to the star wheel 15, an actuator finger 20 is directly turned by each con'trol knob, anda synchronizing Switch 21,'1having' double headed actuating plunger 22, is located in position to -be contacted by the linger 20. At a neutral reference positionof zits associated control knob, the linger 20rests7in the Acenter of the actuating plunger 22 soV that the synchronizing switch '21 is nona'ctuated. Thisneutrlireference position is referred to asA lthe index jposition, and itis seen that whenever the throttle knob 11, pitch knob 12, or bank knob 14 is turned from either side position into its index position, its respective synchronizing switch 21 will be actuated `through one cycle." i 1 The three manual controls 11,312'and 14 are-each preferably provided with position indicating means such as a pointer 24 and a calibrated dial 25, and the transmission ratio between'the knob 'aindthe star vwheel 15 is such that a rotation of one calibration mark causes a displacement of one notch of the star wheel. Thus, for each one-point movement of the throttle knob 11, for example, one of the control switches 17 is actuated on and olf to produce one `pulse, and, `in addition, Whenever the index position is reached, a separate A-pulse will be produced by the synchronizingY switch 21. These control units are shown, described and claimed in a separate co-pending application, Serial N o. 152,042, filed'March 27,1950. i Y 'Y In addition Yto the main' control knobs, a row of five auxiliary function switches 26 (onoftyppe) is provided on the controller unit 9. These manually/operated switches control the Aauxiliary and emergency functions listed above.

Each control switch 17, synchronizing switch 21, and auxiliary function switch 26 is connected through the transmitter relayunit 10 `(to be'described i'n d etail later) into a modulation circuit in the transmitter 7. In this example, ten different audio oscillators (not shown) are prolvided in the transmitter 7, together with thenece'ssary switches 26.

relays and other conventional equipment, each oscillator ,being operatively ,connected .into .the transmitting .circuit when its corresponding energizing means is actuated, as is well known to those skilled in the art. In other Words, a control tone is transmitted for the short period of time taken in turning from one calibrated control knob position to the next position, .or in .throwing one of the auxiliary function switches 26, andthe frequency of `the tone depends upon which particular switch is operated.

Numbers on the output side of the relay unit 10 refer to these ten channels andy show which channel is used for the various controls. ln a preferred embodimentVV of this invention, the frequencies of the ten audio channels were selected as follows: 300, 420, 5-90, 825, 1155, 16.20, 2270, 3180, 4450 and 6250 4cycles per second, for channels 1 through l0 respectively. Y

The transmitting equipment as described may be located at a ground station, as shown in Figure l, or be mounted in a chase car ,or airplane, Aor duplicated in several locations for alternate control. ln the aircraftl ,or other device to be remotely controlled, the transmitted `signal is picked up by a receiver antenna 27. Y

In the receiver 3, he signals are de modu-,lated and amplifiedV in any conventional way and then fed to the selector which contains the customary selective filters (not shown) which pass or reject any particular audio tone according to its frequency. The filters are, of course, .individually tuned to the same frequencies as the respective ten control oscillators, vso that aV l620-cycle signal, v4for example, will be passed by the -l620-cycle filter only, -thus giving ten loutput channels from the ref ceiver and selector unit 3.

It will be noted that'for each attitude control knob l1,1,

12. and 14, in Figure V2, there are three signal circuits, two of which govern movement `of the respective functions in OPPOSit@ directigtls, and the third siringa synchronizing signal at the index position only, as indicated by Athe labels on the respective output leads. These nine Vfunction circuits are connected through thenorrnally closed contacts of one or more' function transfer relays, repre; sented at 29 in Figure 2, to thereby fill nine of the'ten audio channels. Channel number l0 is a transfer channel which is energized Vfor approximately one-half second whenever any one of the auxiliary function switches 2,6 is operated, as will be described in detail later, which operation also actuates the function transfer relays 29 to, v

switch channels Y circuits connected respectively to lthe auxiliary function i Thus, additional circuits are provided, operating through the normally open contacts of the functiontransrfer relays 29:, althonghronly seven such additional circuits are actually shown Vin Figure 2, leaving twol spares. n Y Y In Figure 3, tlie'outpntv of the filter from channel number l0 is connected to actuate 'aesingle transfer relayZQa in the receiver .Output adapter@ to switch @Ontrclcircuit connections from the nine basic attitude circuits to the auxiliary function :circuits which are duplicatesfof the auxiliary switch circuits in Figure 2. The eighteen p ossible control circuits are thus present again in the aircraft in the output adapter4, in Figure 3, as indicated'by the correspondingly labelled Wires.

The three circuitsfrom a single transmitter'controller attitude knob pass through the V,output adapter 4 to control the position of one of three stepping potentiometers 30 in the control unit'S, as shown in lFigure 4. These stepping potentiometers 30 are the controlling members of conventional ,autopilot and throttle servomechanisms which in turn control 'the position 'of a throttle and .pitch and bank'controlsurfaces'ofthe aircraftfli'n the usual manner. l l Y Briefly, the operation ofthe' stelgrpingV potentiometers is as follows: A control pulse'in'the advahce'throttl'' l through 9 to a second set of function throttle potentiometer one increment in the advancing direction. Succeeding pulse signals in this same line will continue to step the potentiometer one increment for each pulse. Similarly, control pulses in the retard throttle line d will actuate the same stepping potentiometer one increment in the retarding direction. When the throttle control knob 11 is turned to the reference index position, an indexing pulse will be sent through the throttle index line e by reason of its synchronizing switch 21. In the control unit 5, the 28-volt indexing pulse will energize a pulsing relay and associated connecting relays (not shown), if the throttle stepping potentiometer is not already in its index position, to drive the stepping relay and potentiometer the number of increments necessary to bring them to index. Thus, the throttle servomechanism, in which the stepping potentiometer is connected, is automatically synchronized with the -controller kno-b whenever the index position is reached. This indexing system is fully shown, described and claimed in the application of Rhoades and Stevens, U. S. Serial No. 217,102, tiled March 23, 1951.

Control equipment for the auxiliary functions, i. e., the circuits controlled by the tive auxiliary switches 26, is illustrated in the output adapter 4 of Figure 3. Here are various types of 28-volt relays which turn on and off the auxiliary or emergency equipment in accordance with the position of the relay contacts. These auxiliary function control circuits are extended through the control unit 5 of Figure 4 and then are routed to the proper actuators as indicated lead. In the control unit 5, a command failure relay 31 acts upon loss of receiver output, to switch all output circuits to predetermined conditions as will be described in full later.

The novel features and combinations of the present invention are mostly to be found in the controller unit 9 and the transmitter relay unit 10, and a detailed description of this equipment will now be set forth. Referring to Figure 5, all wiring in the controller unit 9 passes through a controller receptacle 32 in which each wire connection is identified by letter. Leads from this receptacle connect to the transmitter relay unit 10, and through the latter, connection is made to the transmitter 7 and its power supply so that a transmitter on-off switch 34, located on the controller unit 9 between pin Z and the grounded pin Y, has control of the plate supply of the transmitter, and so that an operation lamp 35 connected between pin a and the +28-volt pin X glows when the entire transmitting system is ready for use.

The poles of the control switches 17, synchronizing switches 21, and auxiliary function switches 26 (Figure 2) are electrically connected to a ground wire 36 coming from pin Y. All control switches are shown in their olf or unactuated positions, i. e., the attitude control switches 17 and the synchronizing switch 21 are in their normal spring-loaded positions, not contacted by their actuating members. The maintain heading auxiliary switch is the only one having its otf position grounded and this will be referred to later.

Auxiliary function lamps 37 may be included to indicate, when lit, that their respective function switch is in its grounded position.

Adjacent each attitude control knob unit is located a locking solenoid 39, further shown in Figure 7. A solenoid plunger 4t) is rotatably connected to a lever 41 which is pivotally mounted on the frame 42 of the controller 9 and which in turn is rotatably connected to a locking stud 44. The stud 44 is slidably supported in a frame-mounted bracket 45 and is positioned to enter and fit one of the tooth spaces of its associated star wheel in a direction perpendicular to the axis of rotation thereof when the solenoid plunger 40 is retracted into the solenoid 39. When the solenoid is energized to retract its plunger, the star wheel and its control knob by the labels for each output n 6 are locked against turning. One end wire 46 of each of the three locking solenoids 39 is connected to +28 volts at pin X and the other end wires 47 are connected to separate pins D, J and P, respectively. The D pin wire of the pitch locking solenoid is also connected, by a cross wire 49, to the on position of the maintain altitude switch. Signal wires 50 from the operating positions 51 of all control switches are connected to the remaining receptacle pins, as shown, for the purposes indicated by the functional headings. Control signals are thus produced by grounding these signal wires 50 whenever the switches are so operated.

In Figure 6 is shown the complete wiring of the transmitter relay unit 10, starting at the left side with a relay unit plug 52 matching the controller receptacle 32 with identical pin letters. In the relay unit 10, a +28- volt bus 54 extends from pin X to a -I-28-volt terminal 55 of an output receptacle 56 which is connected by cable7 for example, to the transmitter 7 and its power supply. From pin Y, the ground wire 36 is extended through the relay unit 10 to a grounded terminal 57 of the output receptacle 56.

The transmitter relay unit 10 contains a locking relay 59, three 0.1 second delay, slug type, function relays 69, 61 and 62, live transfer relays 64, 65, 66, 67 and 68, and live actuating relays 70, 71, 72, 73 and 74, each of the latter being directly associated with a corresponding transfer relay. These relays are all twoposition, multiple pole relays having a relay coil 76, switch poles 77, and upper and lower contacts 79 and 80, respectively, for each switch pole 77. When the relay coils 76 are energized by current ilow, the switch poles 77 are brought down to the lower contacts 80, and when the coils are de-energized, the switch poles 77 spring up to the upper contacts 79.

Pins A, B and C are respectively wired to the upper contacts of the top, bottom, and middle switch poles of the left-hand function relay 60. Pins F, G and H are respectively wired to the upper contacts of the top, bottom and middle switch poles of the center function relay 61. Pins L, M and N are respectively wired to the upper contacts of the top, bottom and middle poles of the right-hand function relay 62. Since the -function relay switch poles are normally against their upper contacts, these first nine pins are normally connected, electrically, to their respective relay switch poles, the latter being permanently wired to positions one through nine, individually, of the output receptacle 56.

Positions one through ten of the output receptacle 56 are extended to enter the transmitter 7, where they are respectively connected in series with the cathode circuits of the ten audio oscillators previously mentioned, for example. Thus, it is seen that whenever a control switch 17 or synchronizing switch 21 is actuated to the opposite position from that shown in Figure 5, the cathode circuit of its respective audio channel is completed to ground to transmit its particular audio tone. As soon as the control switch is released, as when its control knob is occupying one of its calibrated steady-state positions, the audio channel is interrupted. This illustrates the specic method of generating signal tonal pulses in the proper modulation channels in this particular embodiment. The transmission of a signal in channel number l0 remains to be discussed.

Pins D, I and P are respectively wired to the lower contacts of the three switch poles of the locking relay 59. These three switch poles are wired to ground, so that energization of the locking relay 59 grounds pins D, I and P, and, therefore, actuates the locking solenoids 39 at all three attitude control knobs 11, 12 and 14. This simultaneous locking action occurs only when one of the auxiliary function switches 26 is operated and will be referred to later.

Pins S, T, U, V and W are respectively wired to the lower coil ends of the altitude actuating relay 74, headarsenal,

ingnac l g' feiayl- 71,' angelangt actu se gear, actuating, relay 701.;A "Thtupn'er'.coilendslof ,t se ve .actuatingrelays'` thfri, PQS on ofeachfauxiliary function switch Y excv t ,the maintainheading switch, causes enertion` of itsfrespe, tiv ac tuating,relay for asV long as gear transfer'relay 6.4,Qthe other end of which is grounded.

'At the land'ngggearitriansfer relay/,64, the lower contact o'ftheQtop polewired to onercoilend of the lefthand function' r'elay,60,1theothenend of Vwhich connects to lthe 28-volt busv54, andthe lowercontact of the bottom pole is connected to a locking relayvfeed wire 84. This feed wirev 84 Aconnectsto, one coil end-of the locking'relay v59, the otherv end of which connects to the 28-volt bus 54,and av l0() vrnfd.y transfer holding capacitor S7 is connected lacross the coil of the locking relay 59. From the llower vcontactfthe middle pole of the locking relay 59, a transferrchannel feed wire 92 connec'tsr to'position number lO'of the output receptacle 56.

The top pole of thelanding gear actuating relay 70 connects to groundthe same* as both poles of the landing gear transfer relay 64, whiie the upper contact of the bottom pole'of this actuating-relay 70 connects to the bus 54.-

The flap actuating relay 71Vand transfer relay 65 are likewise wired between themselves, to ground, and to the bus 54,l with theseexceptionsv.: the lower contact of the topfpole'of the actuatin'g'relay '71 is wired to the lowercontact of the middle'pole of the center functiony relay 61, andthe lower 'contactof the top pole of the transfer relay `65giswired to onecoil end of the center function relay 61, the other end of which connects to the bus 54.`

Sufficient structure has, thus far beendisclosed to ascertain the basic featuresv of Ythis invention, Taking the landing gear auxiliary functionl switch,l as an example, operation is as follows. Throwing this' switch to the e ctuating relayj 72.,l flap V` on position energizes. he landinggear actuating relay 70, as previously explained., As an immediate result, the 'lower contact of the middle poleL of the left-hand function relay .6(V)-is-grounded throughjthe topv pole of the actuating re1ay`70'which is now in its down' position;. and. the top of the 100fmfd. capacitorv 8i, which was previously charged to +28-volts, is connected to the'ungrounded coil end of the transfer relay 64 through the bottom polerof'the` actuating relay 70,-thereby energizing the transfer relay-64 for a period of time until the capacitor .discharges below a critical value.

Therefore, the .next eventsfollowing energization of the transfer relay 64 :are they grounding of the locking relay feed wire 874 through the bottompole', which starts transmissionof .anaudio signal in channel nurnber Yl0 simultaneouslywith-actuating Ythe locking relay i 59,-V dueto the transfer feed Wire'92, and the ,groundingv of one end of the leftfhandfunction relay 6i)- coil, cansing energization thereof (after its built-in time delay has expired) lbecause of the ,bus54 connected tok the other end,this'latter .groundingrbeing obtained throughV the toppolezof the transfer yrelay 6d. Energization lof the left-hand function relayatnb'rings its middle pole to the, .lo,wer contact, thereof, whicheisV now grounded by theAY actuating. relayv 70,'thereby starting transmission of an audio Ksignal inchannel number 2 whiley channel num-- ber`10 is still actuated.

It isnow ,obvious from ,Figure- 3 that when a rtonepulse. is, being,rec eived, simultaneously f in ,Channels numberi l0 andlfthe resultvis'a 2,8voltsignal ,inA-the .1ower-; landinggear? line,sincethechannel number l0 and ,2W lters are both-passing atctgrrentz.whichV actsto operateV control relays (not shown) to connect the. aircraftrs; power supplytothe single transfer.relay,29a and tothe circuit ofchannellnumber 2. Thisvrsignalpulse actuates a landing gear holding relay 85 inthe output adapter 44 which connects +28volts to output wire-leadingto at landing ,gearrelease solenoid (not shown).,

As the chargel of th'e capacitor 81 is beingremoved through the YVlanding geark transfer relay 6,4,which pref-. erably has about l250lohms resistance, the pull,against` the switch poleI springsreduces until the poles of the transfer relay 64snap back to their upper contactsand this immediately de-energiZes lthe left-hand function relay Y e'hto unground its middle pole and stop transmission of .a tone in,channel'number2.L However, 'thelocking relay V5V9'doesnot ,become immediately deenergi-zed, due to the charge stored on the transfer holding capacitor 87." Approximately one-tenth .to one-fifthV second after de-actuationof thetra'nsfer relayvi, the holding capacitor 87 allows de-energizationof the locking relay 59,` to unlockvthe control. ltnobsvand to stop transmission in channel number l0.V The landing gearauxiliary-funchalfgsecond interval.- There is, therefore, no chance .for Y' the signal pulse to be received-by thewrong control .cir-

cuit, as would be the case if the transfer tone were Vnot Y present during the entire signal pulse when an auxiliary function switch'is operated.V Y

It will also be noted that when the left-hand function relay 60,- in the preceding example, is energized, the channels numberV lp'and 3 will be energized by virtue of the grounding of either the top or bottom pole of this func: tion relay 60.l This will be accomplished at the altitude actuating relay 74 whichhas its-bottom pole connected to ground, and its bottom pole upper and jlower contacts connected Yrespectively to the lower contacts of the top Y and bottom poles of the left-hand function relay 60. Thus, whatV actually happens in this specific apparatusis that a -repeat signal will `also be sent via either channelk number l or 3v, depending on the position of the/altitude. actuatingrelay 74.y This repeat signalwill merely energizrre, in the output adaptor 4, one of the altitude control relays (not as yet discussed).which isl already in a position in agreement with this energization Vso that no change .in the altitude systemV is involved or caused byfoperaton of the landing gear switch discussed above. The repeat signal is merely an incidentalgoccurrencearising-from the.

usepf'the three-pole function-relays 60, 61 and v62.VA Of Y course, nine single-pole functionrelays could-be used, if-

desired, but the repeat signalris-not objectionablel since nothing happensrias faras the controls are concerned. Y

The landing ,gear control function, as described in this embodiment, vprovides-for-onlyl one way action (lowering) L ofthe landing gear-in that itrcannot be retracted since f Yits holding relay 85.3in -the,,outputarlapter 4 remains ener-- choice, and the remaining functions which can be turned olf or on, at will, will now be described.

At the smoke actuating relay 72 both the upper and lower contacts of the bottom pole are connected to the lower contact of the middle pole of the right-hand function relay 62. The top and middle poles of the smoke actuating relay 72 are respectively connected to a first and second condenser and resistor combination 89 and 9i), respectively, and then to ground, instead of only one such circuit at either the landing gear or liap actuating relay. The upper contact of the top pole and the lower contact of the middle pole of the smoke actuating relay 72 are both wired to one coil end of the smoke transfer relay 66, the other end of which is grounded, While the lower contact of the top pole and the upper contact of the middle pole are wired to the 28-volt bus 54.

At the smoke transfer relay 66, the lower Contact of the top pole is wired to one coil end of the right-hand function relay 62, the other end of which is connected to the bus 54. Also, the lower contact of the bottom pole of this relay is connected to the locking relay feed wire 84, and the remainder of the smoke relay wiring is similar to that of the landing gear and ap relays.

In the operation of the smoke function, as the smoke actuating relay 72 is now pictured, the second condenser and resistor combination 99 is charged to +28 volts, while the first combination 89 is discharged, since both ends of it are completed to ground. When the smoke function switch (Figure is moved to the on position, energization of the smoke actuating relay 72 causes discharge of the second condenser combination 90 through the smoke transfer relay 66, causing its actuation, as described for the other transfer relays. In this manner, a signal in channel number l0 is again sent, accompanied by a shorter signal in channel number 8. In the output adapted 4, a 28-volt pulse is thus caused in the smoke lead to which is operatively connected a smoke impulse relay 91. This relay is now energized to connect +28 volts to a smoke signal line cto turn on a smoke generator (not shown) in the aircraft.

When the 28-volt pulse in the smoke lead ceases, due to suicient condenser discharge through the smoke transfer relay 66, the smoke impulse relay 91 will be deenergized but its contacts will remain in the position leaving the smoke generator turned on.

It is now obvious that the first condenser combination 89 has been charged by means of the top pole of the smoke actuating relay 72 occupying its lower contact position, since this relay remains energized all the while the smoke function switch is ou Therefore, when the smoke switch is turned olfj the smoke transfer relay 66 will be actuated in the same manner and for the same time interval as before due to the discharge of the rst condenser combination 89 through the top pole of the smoke actuating relay 72. Accompanying this action, a second signal pulse is transmitted in channel number 8 from the ground connection of the upper contact of the bottom pole of the smoke actuating relay 72, as well as the attendant transfer pulse in channel number 1G. This time, the smoke impulse relay 91 will be operated to open its contacts, since with every other signal pulse the contacts open and with every other alternate signal the contacts close.

Since both on and off smoke pulses are transmitted in channel number 8, the lower contact of the middle pole of the right-hand function relay 62 could actually be directly ground, if desired, as indicated by dotted lines 94 in Figure 6. However, the smoke actuating relay 72 is shown herein as being wired similarly to all other actuating relays.

The action of the locking relay 59 is also evident whenever one of the auxiliary function switches 26 is operated. The locking relay 59 is energized simultaneously with the transmission of the transfer pulse in channel number l0 so that none of the attitude control knobs can be turned while any of the function relays have disconnected the pitch, bank or throttle signal leads from their respective nine audio channels. This prevents the remote operator from inadvertently or other wise turning a control knob when it would naturally have when the locking relay 59 is energized, but detains its deenergization long enough to insure that the transfer tone overlaps the function tone at its rear edge.

The remaining two sets of actuating and transfer relays are for contro-l of the automatic heading and automatic altitude systems in the autopilot of the aircraft 1. These functions may be turned on and `olf any number of times similarly to the smoke system, due to the double capacitor circuits. The on and oif signals of either the altitude or heading System, however, are accomplished in two different modulation channels. As shown in Figure 6', the upper and lower contacts `of the bottom pole of the heading actuating relay 73 are wired respectively to the lower contacts of the bottom and top poles of the center function relay 61, while the lower contact of the top pole of the heading transfer relay 67 is wired to the upper coil end of the center function relay 61 in parallel with the lower contact of the top pole of the flap transfer relay 65. The altitude actuating relay 74 connections have previously been described as leading to the left-hand function relay 60, and the lower contact of the top pole of the altitude transfer relay 68 is connected to the upper coil end of the left-hand function relay 60, in parallel with the lower contact of the top pole of the landing gear transfer relay 64.

The maintain heading, on signal is, therefore, transmitted in channel number 6, maintain heading, off signal in channel number 4, "maintain altitude, on in channel number 3, and maintain altitude, olf in channel number 1. Thus, all channels are utilized to carry two functional signals each, except channels number 7 and 9, which are unused in this particular apparatus for an auxiliary function.

For the maintain heading system, a heading latching relay is located in the output adapter 4. This relay contains an on coil 96 and an off coil 97 which govern the position of a single pole, double throw relay switch 99. When the on coil 96 is energized, the relay switch 99 will be connected to a +28 volt position 100, and when the o coil 97 is energized, the switch will be connected to an off position 161 which leaves the switch circuit open. The on coil 96 is connected t0 be actuated from a control pulse signal in channel number 6 when the single transfer relay 29a is also energized, and the olf coil 97 is connected to be actuated by a signal in channel number 4 when the single transfer relay 29a is energized.

The pole of the relay switch 99 is connected by a heading signal line n through the operating contacts of a heading control relay 102 in the control unit 5 to a normally closed position of a heading failure switch 104 from which the automatic heading system in the autopilot obtains its signal.

It is thus seen that a 28-volt pulse is produced through the on coil 96 when the heading function switch on the controller 9 is moved to the on position to turn on the automatic heading system in the aircraft by energizing it from the 28-volt power supply, and that a 28-volt pulse is produced through the off coil 97 when the heading function switch is moved to the off position to turn off the heading system.

The actuating coil of the heading control relay 192 is operatively connected into the bank indexing circuit so that the heading signal line n is opened whenever the bankfcoutroly members `.are out rof' the index (levelflight) position; .and completed when these membersraresfin, the.. Thus,-: if athe. maintainfheadingA switch',-

indexl position.;

is Ourthebankcontrol-knobfll may be operated as usual,

altitudefswitchis turned. on,- the pitchnlocking solenoid in-the-controller fis energized so that the pitch control knob 12 cannot beturned from itsexistingfposition. This is accomplished. bythe crossiwire t9-(Figure -5) which completes the p itch locking1 solenoid, only, to` ground through theioperating .position151 lof the maintain altitudef; switch when this switch ismoved to the on position.-

Imthe outputadapter 4, an altitudeflatchingxrelay 105 andl altitudeL signal line k are provided to make :the .on

and-olfremote controlsignalsaetuate the automaticaltitude system the'l same-as the .heading system. The;only difference is thatvin thecontrol unit 5,- no control Vrelay for.the:altitude'` system is provided `in kthe -pitch index-circuit. Thealtitudesignal-line kvleadsdirectly` to anorma1ly-closed position of an altitude.' failure switch 106- (Figuref4) from -which'the altitude system in the-auto pilot receivesits signal.

This completes the description of 4the'automatic dupleX ing E-rneans which makes possible lthe control of vanytauxiliaryyfunctions-from a single switch or knob, and ,which gives substantially continuous control since the maximum waitingrtime between the operation'of any twocontrolsis-only approximatelyfone-half second.` Since the. primary flight attitude control signals are all transmitted' without actuation of any of the transfer relays, these threefcontrolsl (throttle, pitch and bank) can be operated simultaneously, no matter what the direction of movement of each.

inthe Control` unit 5, `the heading failure switch 164` andthe altitude failure switch vlilo are both actuated by` thefcommand failure relay 31; along with a l0-degree banktswitch 167, bank failure switclrlllg, pitchfailurev switch 1l9,smoke failure switch lll, and throttle fail-- ure switch .112.. As seen in Figure 4, whenever-the command failure relay 31 is energized, therthrottle, pitch, andt-bankpotentiorneters dvare indexedgthe smoke functionV is turned on, automatic altitude controlisturned on,

automatic directional controlv is turned o; and thev aircraft is put intoa `=40degree left'bank `by taking the'- bank signal from a tapped connection: 114 on the bank stepping-,po-tentiometer. The command failure relay 31 is `energized as follows:

A',command failure signal line a leads fronr'the vungrounded end of the command failure relay 3l to one-Y*n contact of arst motor-operated delay relay 115 inthe e output adapter if The other operating contact of'thisV motor relay is connected to +28 volts so that energization of the motor delay relay 1.5 ycauses energization of the command failure relay 31. The motor delay relay 115 isoperatively wired,'through the contacts of a second motor delay relay llo, to the receiver and selector-3,

where it is arran'r'd byl suitable means (not shown) Vto.v be connected to +23 volts whenever the transmitter carl rier wave drops'` below` a predeterminedintensitylevel, or when the receiver Voutput'disappears duexto. otherf failure.

Thefiirst .motorbpcrated delay relay 115,: in` this .pan

ticularzeinbodiment, has an adjustable delay of froml to -39 seconds. This delayproyision allows any momentary Vfade-out of the radio signal tobe unnoticeable .as far as the command Vfailure systeml is concerned. The second motor delay-relay 116 .gives approximately a .l-

minute delay for the purpose of preventing-the command failure-cricuit from` operating immediately Afollcm/ing launchingof the aircraft 1,1 while' it is climbing'toa reasonablysafe-altitude; before going `Vinto the.fitti-degreeVV .operative for-'any reason.

bank. '.at, constant a altitude,vv if the transmitting :orr'receivi'ngVl means should fail.. After .the.ilminute interval,- the con'-,

tacts.of-.thef second rnotorifdelayl relay 116 close and :re-

main closed since. it-,is :a1-reset' type irequiring ,a manual. operation,to-re-openit after once closing..

Energization of the second niotoridelay relay 116 may,

be startedby aninitiating relay 117 which is itself 'en-1 erg'ized from theinstant of forward motion Vof the aircraft when launched Vuntil '.it4 leaves contact with the :ground orilaunching'device. kThel initiating relay 117 is also reset type which its contacts, which form the v.com-z plete energization circuit ofthe second motor delay relay llo, remainzclosed after energization ceases until manually openedfagain:

Energization'of' the..-initiating relay 117 may be accomplished by' any-suitablermeans, such as that'shownwV in Figure 8,v for example.; Here thetaircraft 1 is supported by alaunchingtdevice'1201operating on-a track-.lilland`A` adapted to be driven by rocket motors l22. in the launching devicerlilhya rocketlirin'g. switch 124-is connectedto'. energize the Yrocketzmotors 122 .at the time of launch-A iug,; when .thisl ringswitch. llZl is closed, preferably by remote control means.` Also connected to be energized bythe ringswitch 124,1.when closed, is a tiring relay 125' whosev relaylcontacts'lrwill complete a circuit` between ground: andfaspringcontact `F127 mounted to project upwardly fromthewlaunching device 120 through an.` insulated support 129." A ContactA pad 130,' mounted flush withv the botto/ru vsurface ofthe aircraft 1, and insulated"therefrom,v is arranged to makefelectrical con# tact lwith. the'spring'contact l27 `when the'craft is .in launching position'. The contact pad 13@ is wired to vone coil end of the. initiating relay 1l?, the otherendof which is wired to +28 fvoltsofthe aircrafts power'supply.'

Before'launching the aircraft l,v the firing relay 125,'y

initiating-relay1117, and secondmotor delay -relay 116 are all cle-energized and theiroperating contacts are opem When"thefuingswitchl 124 is closed, thefaircraft'and launchingdevice accelerato alongl thel track lill-and theYV firing relay contacts 126 close-to energize the-initiating relay 117 Sin thel aircraft; This closes the circuit ofthe secondmotor delay relay- -116 and starts the l-minute delay-periodbefore theicornmand failure circuit to the first motor-operated delay relay 11S cau becompleted. The` aircraft engine is also *acceleratedlat'thisftirne, althoughl theY means `forfdoing-thisis vnot shown. WhenV the aircraft 1 separates from-'the launching device 120 at flying speed and `the contact v pad:v 13ll-thus breaks connectionffwith v f the springhcontact 127,1.the'initiating relay'll/ will bedeernergized` for the-rest ofH the ight, but the circuit to theV second motor delay relay lloremainseclosed', asy stated -'previously/7. As y-soor1-=as-the-seeond motor delay relay contacts are closed at theend ofthe 1-minuteperiod, Y normal -ilying conditions are reached, and the command r failure -system-isfin :readinessfOroperatiOn, subiec'tA only totherstfmotor-operated-'- delay relay 115, which can oper-ate on or olf any number-'of times.

Thus, it 'is seen. thatathorough emergency procedure is provided in the event of the-radiosigoal becoming in-V Additional safety is Vincorporated over the-'normalfmethods infthat-a .commandsignal failure during,iorirnmediately following, launching is deferred until a predetermined altitude is reached-g so that the-aircraftlisunder'steady predictable controll jv at all times: This predetermined altitude Vwill be reached since the controls are xed, during launching, in positions causing a normal climb. Y After restoration'of signal power following acommand failure, thecommand failure I relay 31 Twill 'again become fle-energized Vand the aircraft 1.1 is thereby brought back to normal control at throttle index'fpitchwindex, andiba'nk-sindcn positions. p

In anotherembodiment` of this invention, e auxiliary' functionncontrolsrare @transmitted inztheir properfchane-V nels' and 5to theirlrespectiveV Ycontrol':circuits in th'efoutputadapter-'f4 b`y1-means1fofSal-differenti apparatus; asshowm in Figure l0. In this alternate apparatus, a modified transmitter relay unit 10a incorporates a continuous pulse generating means from which the auxiliary function signals and function transfer signals are taken. This pulse generating means comprises a constant speed motor 131, a motor driven starting cam 132, a motor driven holding cam 134, and a motor driven signal cam 135, all three cams revolving at the same speed. An actuating surface 136 on each cam is provided to close a switch arranged to be contacted by the actuating surface 136. In this manner, a starting switch 137, holding switch 139, and signal switch 140 are respectively closed when contacted by their corresponding cams.

On the starting -carn 132, the actuating surface forms about one-fth of the total cam circumference; on the holding cam 134, the actuating surface forms about fourfths of the circumference; and on the signal cam 135, the actuating surface forms about two-fifths of the circumference. These cams are carefully aligned with respect to each other so that, when rotating in a counterclockwise direction, the starting switch 137 and the holding switch 139 are closed simultaneously and the signal switch 140 is closed one-fifth of a revolution of the cams later. The resulting pattern or combination of pulses is shown in Figure 9 where an open switch condition is ofi and a closed switch condition is on With a motor driving the cams at a speed of 120 R. P. M., for example, the pulses will have a period of 0.5 second, and the widths and relative phases of the pulses are as indicated in Figure 9. It will now be explained how the signal switch 140 produces the auxiliary function signal tone in one of the first nine channels; the holding switch 139 produces the transfer tone in channel number 10 overlapping the auxiliary signal tone, and the starting switch 137 provides a means of preventing a partial signal pulse from being transmitted, no matter at what instant the auxiliary function switch on the controller is operated.

Referring again to Figure l0, only two auxiliary function circuits are shown, altitude control and smoke signal control. These represent the only two different signal circuits of this invention, the first requiring on and off signals in two different modulation channels, and the second requiring only one -channel for on, or for on and olf signals. In the modified transmitter relay unit 10a are located a four-pole smoke control relay 141, two-pole smoke holding relay 142, four-pole altitude on relay 144, two-pole altitude holding relay 145, and four-pole altitude off relay 146, besides the locking relay 59. Initiating signals from the on-off smoke and altitude function switches are applied at the lower ends of these relays through pins K', L', M and V of relay unit plug 52a, which signals consist of grounding these respective relays at their lower ends, similar to the method of control in the first embodiment.

At each of the four-pile relays, the pole immediately under the top pole will be referred to as the second pole, and the pole immediately under the second pole will be referred to as the third pole.

At the smoke holding relay 142, the upper coil end is connected to the lower contacts of the bottom poles of the smoke holding relay 142 and the smoke control relay 141. The bottom switch pole of each smoke relay 141 and 142 is connected to a +28 volt bus 54a. The top switch pole of the smoke holding relay 142 is connected to one side of the starting switch 137, the other side of which leads to the bus 54a. T'he upper contact of the top pole of the smoke holding relay 142 is wired to the lower contact of the third pole of the smoke control relay 141 and also to the upper coil end of this control relay 141.

The third switch pole of the smoke control relay 141 is wired to one side of the holding switch 139, the other side of which is bussed. The lower contact of the second pole of the smoke control relay 141 is grounded and the second pole is wired to position number l on the output receptacle 56, which position sends the transfer tone in channel number 10 as before. This second pole also connects to one coil end of the locking relay 59, the other end of which is connected to +28 volts as in the previous embodiment. The individual locking solenoids 39 in the controller 9a are energized, as before, through pins D, .l and P which are grounded by actuation of the locking relay 59, so that locking of the three control knobs 11, 12 and 14 is accomplished during the transmission of the transfer tone. The lower contact of the top pole of this smoke control relay 141 is wired to position number 8 of the output receptacle 56, and the top pole connects to one side of the signal switch 140, the other side of which is grounded. The constant speed motor 131 is operatively connected in the 28-volt power supply in the relay unit 10a.

In the modified controller unit 9a, the smoke function switch 26a is a single pole, double throw switch having its pole grounded and both throw positions connected to pin V on controller receptacle 32a. The altitude function switch 26b is a double pole, double throw switch having both poles grounded, the on and olf positions of one pole both connected to pin L', and the on and off positions of the second pole connected respectively to pins K and M.

Operation of the smoke function system is then as follows: Assuming at iirst that the smoke switch 26a is positioned midway between on and off, both the smoke control and holding relays 141 and 142 are de-energized and occupying the position shown. Therefore, nothing is happening as a result of the rotation of' cams 132, 134 and 135, since their switch circuits are dead-ended either at the relay contacts or at the controller end of the relay coils. If the smoke impulse relay 91 in the output adapter 4 is in the off position (not connecting the smoke generator to +28 volts), for example, moving the smoke function switch 26a to its on position will ground the two smoke relays 141 and 142 immediately if the starting switch 137 is closed, or at the next time the starting switch is closed as the starting cam 132 rotates. When this happens, the smoke control relay 141 is energized due to its connection to +28 volts through the upper contact of the top pole of the smoke holding relay 142. Actuation of the control relay 141 feeds +28 volts to the top of the holding relay through the bottom pole of the control relay 141, thus causing its actuation, but in the meantime, the third pole of the control relay 141 connects the top coil end of its relay to +28 volts from the holding switch 139 so that the control relay 141 remains energized even though the starting circuit through the top pole of the holding relay 142 has been broken.

When the control relay 141 was iirst energized, its second pole grounded the control circuit of channel number 10, thus starting transmission of the transfer tone, and simultaneously energizing the locking relay 59 to operate the locking solenoids 39 (only one of which is shown) in the controller 9a through pins D, I and P. While both smoke relays 141 and 142 rema-in energized, the signal switch 140 will nex-t be closed approximately 0.1 second after `the transfer tone was started, as: shown in Figure 9. This grounds the signal circuit of channel number 8 through the top pole of the control relay 141, and the function signal will, therefore, be sent in channel nurnber 8 (while the single `transfer relay 29a in the output adapter 4 is energized) for a time interval of approximately 0.2 second, as determined by the closing and opening of the signal switch 140. T'he smoke function in the aircraft 1 has now been turned on, according to the description given previously.

Next, when the holding switch 139 opens, the control relay 141 opens, stops the transfer tone in channel number l0, .and unlocks the attitude control knobs. Initially, the holding relay 142 was energized only by the fact that the bottom pole of the control relay 141 was closed against its lower contact. After the holding relay 142 did begroomerofthe startingcam 132 wilY haveno effect :onfth'e 1smoke function, sincerthetoyg:A pole: of -th'eaholding :relay 142'. ist.

dead-ended'againstits lowerscont-act.` Onlyzone Vsignal pulse-*has thusfbeensentxin channel numberj It willbefnoted againv thatif the smoke function switch.. 26ansv operated betweenV two on pulses -.ofthe starting switch;137, .nothing .will happenuntil the neiotstarting pulse arrives,'thus preventing .the transmission of afpartialsignal pulse which might not .be properly received',v lf .the function switch is operated during a starting pulse, the transmittingqsequence .will fproceedfirnmedia'tely, and the only dilerencewill be a shorter transfer tonefthan normal, butstill overlapping. the, signal toneaatzboth ends.

If 'ther-smoke' function ,switch'2ettis :now moved vto the offA position,I the holding relay rv142 will ,be deL-energized when the switch isbetween-the on Vand-:off positions, thusV connecting the topv pole of theholdingrelays142 tothe. top ofthe coil ofthe controlzrelay 141l andzsettingup.- thev relays for another signal sequence when the starting switch' 13.7 i-s-next closed. This is .true-becauseintheoff position of the smoke switch 26a, both relays 141 and :142 are grounded again.v at theirlower ends.. Therefore, another signal tone will be transmitted in-channel number 8, at

thesame time asthertransfer tone -inchannel number. l0-

is sent, to furnish another pulse to thesmoke kimpulse relay 91in the output adapter 4. OfA course, the. controller-wire -to the off position of the smokeswi-tch 26a couldl be omitted, but in that event, another-.smoke signal. pulse could-not be-transmitted until the switch'was moved .back to the on position.

To secure on and off signals in two different modulation channels for the automatic -alt-itudecontrol system,'for exam-ple, four relaysrcouldbe used tofprovide a'double set similar tothe smoke control and holding relays 141 and-142, However, three'relays can be made-to do the same job, as will now'. be'described. .The altitude on relay 144- is connected at its lowerend to pin K'., lthe altitude holding relay 1451to pin L', and-the altitude oit relay 146 to lpin M of the relay unitplugpSZa With the connections to the altitude function-switch 26h as previously described, it is seenthat in the off position of this switch, the altitudefholding relay V145 and off' relay 146y are grounded at their lower ends, andwh'enthe altitude switch 26h is in the on position,` the holding relay 145A and on relay 144 are likewise grounded.

The altitude on and oif relays 144 and.146=are wired identically with each other with'one exception. The lower contact of the top poleiof the, on. relay 144 isi wired into channel-number 3, whilejfthe lower contactof the top pole of the ot relay 146 is wired into channel number l; Otherwise, the corresponding poles and co-ntacts of these two lrelays are connected directly to each other, and they are each connected `to the altitude holding relay 14S exactly like the smokeV control relay 141 is con-V nected to the smoke holding relay 142..

Operation o-f the altitude system isV thusidentical to the fromone .position .to the other. This circuit breaking between'the two 'positionsv .ofthe function switchesis de.

pended upon for enabling a signal. pulse to be transmitted,

sincethe holding relays 142 and 14S'are continuously energized as longasl the function control switches are left-in any one position.

ylinthe apparatus ofF-igure l0, no function relays such .as thefrelays 60, 61 and 62 in Figure 6 arelused.` The primary attitude control circuits, such as increase .pitchf and pitch index, contact of the top pole ofthe auxiliary Vfunction relay assigned to the same respective channel, so that the iirst nine output circuits from the relay unit 10a are ready for use when. grounded individuallybyrfthe controlknobs .or in combinationwith thefcircuit ofichannel..number 10' by operation'of an auxiliary function .switch This alternate embodimentpresents certain advantages over .the structure of .Figure 6. First,-.no delay relays or.

holding--condensers'are necessary` to provide sequential operation when one.of=the actuating; relays -is energized. All poles of any relay. in Figure Vl() areswitched from one position to the otherin a normal, vsubstantially .simulf taneous manner', and .more positive contact action is thus obtained. Second, a .possible dropin. supplyyoltage from. 28 volts, tofsay 22 or24 volts, will not adverselyaffect.

the operation of any of therelays, whereaswith the timingv condenser circuits .ofthe first embodiment 28hvolts is arelatiVely-l'ow charge in .the `first place, anda voltage drop in' thepower supply to anunexpected .low value might prohibit the desired 1 relay action-whenthe con-.

densersr are' discharging.v The operation of the-second` embodiment does A'not involve such critical .adjustments or conditions for proper control.

In the.-v case of the. secondembodiment, as shown in Figure` 10,' the: pitch control knob, only, may be. locked* Whenrautomatic .altitude control is turned on, ifdesired, by thersame'means as1in'Figure.;6,since the locking; solenoids l39 yare in vthree vseparate circuits; Thefonly thing that Ymight be called a-disadvantage .of'this alternateauxiliaryfunction-apparatus is; that a, slightly longer time may be involvedyfromf-the :moment of'auxiliary function switch operation tothe moment when the control knobs 11, 12 and 14aregreleased from their locking solenoids 39. The maximum time for-v this interval,- however, is

' only using the pulse widths andspeeds .thereinxindicate TheV 0.8 second, 'asrcan be seen fromaFigure, when average waiting time after operatinganeuxiliary function switch and beforeA operating a `primary -control knob. thereafter is in the neighborhoodv of0.'6 second orless,

which still givesV a 'nearly' perfect sense;of`continuous-.

control.

Another point which shouldbe noted from the foregoing specicationiis .channels Vcan be continued further to obtain'fstillfmore control circuits` in the output adapter 4 from the same number of available channels in thefradio link, if def sired. For example, the present embodiments-startwith l() available channels, one ofrwhich is used'solely asa transfer channel to make available-at the output -a selection of'twofunctions for each ofgthe remaining nine `channels. This results in a total of 2(10i-1), orl 18,

method of operation of the smokeV function except that.Y

automatic altitude equipment for t-he autopilot by use ofY the altitude latching relay, 195, as previously described. Again, shifting the altitude switch 26h-from on to oft" makes use-of the off and holding rel-ayv 1.46and 145 toY send function signal tones in channelsnumberl` andlO. j Th'eground connection tothe altitudeholding relay 145.-

is openedwhenever the-altitude switch 26h. iszswi-tchedV functional control circuits.

. Now av second channel could also be usedV as another duplicator of the remaining'channels. In this manner, a totalof V3(10-2), or 24, functional control'circuits could be obtained. Using three of the original l() chan- Vnels'for transfer'purposesonly, a total of 4(10-3), or

28, functions Vcould be controlled, and so on, `buteach additional transfer: channelV used. in .this manner producesV a lesser and lesser gain, making it less and less practical toV Y provideA the extratransfer'channels necessary to achieve the maximum possible number. ofl control functions Vby this method. v However, the teachings-ofthis application Y Vinclude .theuseof 'a plurality of transfer channels, aswell as only one transfer channel, since all that is necessary are directly connected into theV lower that the yduple'xing of modulation area/601 to continue this duplexing procedure is to supply the additional lfunction ,transfer relays, which makes it possible to 'transmit three or more audio tones simultaneously.

It is Ythus seen that our invention provides a complete, remote, radio control system having duplexing means for vobtaining a great many more control functions than there are modulation channels in the radio control link, and it provides this means in such a completely automatic way that a substantially continuous control system is provided, which necessitates the operation of only one control member to get practically instantaneous response from any of the control functions. This system provides complete control, including automatic emergency operation, ofan aircraft, test missile, or the like, from launching through landing, and `safety features provided by the control knob locking solenoids ymake it impossible for the remote operator of the controller unit to operate the system incorrectly.

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail, construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages.

While in order to comply with the statute, the invention has been described in langauge more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise the preferred form of several modes of putting the invention into effect, and the invention is therefore, claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

What is claimed is:

l. In a remote control system for controllinga device having a plurality of movable cont-rol members, wherein a remote radio transmitter having a given number ,of fixed modulation channels transmits modulated control signals to a receiver `and selector located in said device for filtering andapplying said signals to control circuits connected to operate said control members; means for individually cont-rolling more control circuits than available channels, which comprise transfer means connected to'be momentarily energizedby a signal ina first one of said channels, afirs't group of said control circuits connected respectively to the outputs of the remainder of said channels by said transfer means when Vsaid transfer means is deenergized, a second group of said control circuits connected respectively to the outputs of said remainder of channels by saidtransfer means when said transfer means is energized, a plurality of primary manual control members respectively connected to switch on and off any `of said remainder of modulation channels only, a plurality of auxiliary manual control members, each having means for completing an electrical circuit, and automatically timed actuating means connected to operate in response to vcompletion of each of said electrical circuits, each of said actuating means comprising means for switching on said first channelto energize said transfer means, means for switching on a corresponding one of `said remainder of channels while said first channel is still on, means for switching off said corresponding one of said remainder of channels after a predetermined time interval and while said first channel is still on, and means for switching off said iirst channel after a second predetermined time interval, to de-energize said transfermeans.

2. In a remote control system for controlling a device having a plurality of movable control members, wherein a remote radio transmitter having a given number of fixed modulation channels transmits modulated control signals to a receiver, and selector located in said device for filtering and applying said signals to control circuits connected to operate said control members; meansl for individually 18 controlling more control circuits than available channels, which Icomprise transfer means connected to be momentarily energized by a signal in a first one of said channels, a first group of said control circuits connected respectively to the outputs of the remainder of said channels by said transfer means when said transfer ,means is deenergized, a second group of said control circuits connected respectively to the outputs of said remainder of channels by said transfer means when said transfer means is energized, a plurality of primary manual control members respectively connected to switch on and off vany o f said remainder of modulation channels only, a plurality of auxiliary manual control members each having means for completing an electrical circuit, and automatically timed actuating means connected to operate in response to completion of each offsaid electrical circuits, each of said actuating means comprising means for switching on said first channel to energize said transfer means, means for switching on a corresponding one of said remainder of channels while said-first channel is still on, means for switching off said corresponding one of said remainder of channels after apredetermined time interval andwhile said first channel is still on, means for switching off said first channel after a second predetermined time interval, to de-energize said transfer means, and means for locking and unlocking said primary control members simultaneously with the switching on and off, respectively, of said first channel.

3. In a remote control system for controlling a device having a pluralityV of movable control members, wherein a remote radio transmitter having a given number of fixed modulation channels'transmits modulated control signals to a receiver and selector located in said device for filtering and applying said signals to control circuits connected to operate said control members; means for individually controlling more control circuits than available channels, which comprise transfer means connected to be momentarily energized by a signal in a first one of said channels, a rst group of said control circuits connected respectively to the outputs of the remainderof said channels by said transfer means when s ai-d transfer means is de-energized, a second group of said control circuits connected respectively to the outputs of said remainder of channels by said transfer means when said transfer means is energized, a plurality of primary manual control vmembers respectively connected to switch on and olf any of said remainder of modulation channels only, a plurality of auxiliary manual on-off Atwo-position control members,- andautomatically timed actuating means connected `to operate in response to movementof each of said auxiliary control members to one of said positions, each of said actuating means comprising means for switching on said first channel to energize said transfer means, means for switching on a .corresponding one of said remainder of channels while said first channel is still on, means for switching off said corresponding one of said remainder of .channels after a first predetermined time interval and while saidiirst channel is still on, and means f or switching off said first channel after a second predetermined time interval, to de-energize said transfer means.

4. In a remote control system for controlling a device having a plurality of movable control members, wherein a remote radio transmitter having a given number of fixed modulation channels transmits modulated control signals to a receiver and selectorlocatedin said device for filtering and applying said signalsto control circuits connected to operate said control members; means for individually controlling more control circuits than available channels, which comprise transfer means connected to be momentarily energized by a signal in a first one of said channels, a first group of said control circuits connected respectively to the outputs of theremainder of said channels by saidtransfer means when said transfer means is de-energized, a second group of said control circuits connected respectively to the outputs of said remainder of channels by said transfer means when said transfer means is energized, a plurality of primary manual control members respectively connected to switch on and off any of said remainder of'modulation channels only, a plurality of auxiliary manual on-off two-position control members, and automatically timed actuating means connected to operate in response to movement of each of said auxiliary control members to one of `said positions, each of said actuating means comprising means for switching on said rst channel to energize said transfer means, means for switching on a corresponding one of said remainder of channels while said first channel is still on, means for switching off said corresponding one of said remainder of channels after a first predetermined time interval and while said first channel is still on, and means for switching olf said first channel after a second predetermined time interval, to de-energize said transfer means, and additional automatically timed actuating means connected to operate in response to movement of each of said lauxiliary control members to the other of said positions, eachof said additional actuating means comprising means for switching on Vsaid tirst channel to energize said transfer means, means for switching on a second corresponding one of said remainder of channels while said first channel is still on, means for switching off said second corresponding one of said remainder of channels after a predetermined time interval eoual to said rst time interval and while said rst channel is still on, and means for switching off said first channel after a predetermined time interval equal to said second time interval, to de-energize said transfer means.

5. Apparatus in accordance with claim 4 including means for locking and unlocking said primary control members simultaneously with'the switching on and off, respectively, of Said first channel.

6. In a remote control system for controlling a device having a plurality of movable control members, wherein a remote radio transmitter having a given number of Xed modulation channels transmits modulated control signals to a receiver and selector located in said device for ltering and applying said signals to control circuits connected to operate said control members, means for individually controlling Vmore control circuits than available channels, which comprises transfer means connected to be momentarily energized by a signal in a first one of said channels, a rst group of said control circuits connected respectively to the outputs of the remainder of said channels by said transfer means when said transfer means is de-energized, a second group of said control circuits connected respectively to the outputs of said remainder ofrchannels by said transfer means when said transfer means is energized, a separate pulse producing means for momentarily'energizing each of said control circuits individually, a first group of said pulse producing means each respectively connected to produce pulses in only one of said remainder of modulation channels, when operated, and a second group of said pulse producing means all connected to produce a transfer pulse in said first channel, when operated, which energizes said transfer means, and each of said second group respectively connected to also produce a function pulse in only one of said remainder of channels while the pulse in said first channel is present, whereby operation of one of said rst group oftpulse producing means causes energization of a corresponding one of said first group of control circuits and whereby operation of one of said second g-roup of pulse producing means causes energization of a corresponding one of said second group of control circuits.

7. In a remote control system for controlling a device having a plurality of movable control members, 'wherein a remote radio transmitter having a given number of fixed modulation channels transmits modulated control signals to a receiver and selector located in said device for filtering and applying said signals to control circuits connected to operate lsaid control members, means for individually controlling more'control circuits than available channels, which comprises transfer means connected toV be momentarily energized by a signal in a first one of said channels, a first group of said control circuits connected respectively -to the outputs of the remainder of said channels by said transfer means when said transfer means is de-energized, a second group of said control circuits connected respectively to the outputs of said remainder of channels by said transfer means when said transfer means is energized, a separate pulse producing means for momentarily energizing each of said control circuits individually, a first group of said pulse producing means each respectively connected to produce pulses in only one of said remainder of modulation channels, when operated, a second group of said pulse producing means comprising a plurality of on-off, two-position electrical function switches, relay means associated with each of said function switches, means for supplying electrical power to said relay means, each relay means connected in series with said power supply means and its associated function switch, to be operated from an oif position to -an on position when its associated function switch is moved from 'off to on and when said power supply means is opera- -tively connected, a channel selecting switch at each of said relay means connected to be closed when said relay means is operated from oi to on, to select, but not to energize, a corresponding one of said remainder of channels, and timing means operatively connected by each of said relay means, when so operated, to transmit a transfer pulse in said first channel and to transmit a function pulse in said selected channel falling within the width of said transfer pulse, said timing means being adapted and arranged to cause transmission of only one transfer pulse and one function pulse when any function switch is moved from off to on.

8. Apparatus in accordance with claim 7 wherein said timing means comprises, at each of said relay means, a

capacitor connected in a charging position when its respective relay means is in its off position, a discharging relay having a coil permanently wired a-t one end thereof to one end of said capacitor, said capacitor being switched from said charging position to a position connected across said discharging relay coil when said relay means is moved from4 off to on, a pair of transfer contacts operated by said discharging relay and connected in an energizing circuit for said first channel, said transfer contacts arranged to cause lcompletion of said rst .channel energizing circuit` while said discharging relay coil is carrying discharge current from said capacitor, a pair of function contacts operated by said discharging relay, said function contacts arranged to cause completion of an energizing circuit for the channel selected by said channel selecting switch when said discharging relay coil is carrying said current, wherein the energizing circuit for said selected channel contains delay means operating to delay the energization of said selected channel for a predetermined'interval after said function contacts reach their energizing position, wherein the energizing circuit for said rst channel contains holding means operating to delay the de-energization of said first channel for a predetermined interval after said transfer contacts reach their de-energizing. position, and wherein said power supply means is operatively connected at all times when said remote cont-rolling means is turned on.

9. Apparatus in. accordance with claim 7 wherein said timing means comprises, at each of said relaymeans, a capacitor'connected in a Icharging position when its respective relay means is in its oi position, a dischargingV relay having a coil permanently wired at one end thereof to one end of said capacitor, said capacitor being switched from said charging position to a position connected across saiddischarging relay coil when said relay means is moved from off to on, a pair of transfer contacts operated by said discharging relay and connected in an energizing circuit for said rst channel, said transfer contacts'arranged Ato` cause completion of said first channel energizing circuit 21 while said discharging relay coil is carrying discharge current from said capacitor, a pair of function contacts operated by said discharging relay, said' function-contacts arranged to cause completion of an energizing circuit for the channel selected by said channel selecting switch when said discharging relay coil is carrying said current.

10. Apparatus in accordance with claim 9 wherein the energizing circuitfor the channel selected by said channel selecting switch comprises a delay relay having operating contacts normally positioned to connect said first group of pulse producing means to said remainder of modulation channels, respectively, and positionedl when said delay relay is energized to connect said channel selecting switch-to its respective selected channel, and wherein the energizing circuit for said first channel includes holding means operating to delay the de-energization of said first channel for a predetermined interval after said transfer cont-actsl reach their de-energizing position.

1l. Apparatus in accordance with claim 7 wherein said power supply means includes a cam-operated starting switch continuously opened and closed at a constant frequency, the closed interval thereof being a relatively small fraction of the period, and wherein said timing means comprises a cam-operated holding switch continuously opened and closed at said constant frequency, its closed interval starting during the closed interval of said starting switch and continuing for a relatively high percentage of said period,` a cam-operated signal switch continuously opened and closed at said constant frequency, its closed interval startingand ending during the closed interval of said iolding switch, a pair of holding contacts aty each of said relay means, said holding contacts connected to said holding switch and respectively operated by their associated relay means when reaching said on position to hold said associated relay means in said on position until said holding switch opens, a pair of transfer contacts operated byr each of said relay means and each pair`connected inan energizing circuit for said first channel, said transfer contacts arranged to energize said first channel while their respective relay means is in said on position, each of said channel selecting switches connected to said signal switch, and power supply disconnecting means operating at each ofl said relay means in response to movement of its respective relay means to said on position to disconnect said power supply means from that relay means until its associated function switch is moved from its on position.

l2. Apparatus in accordance with claim ll wherein each of said power supply disconnecting means comprises a :disconnect switch connected in series with said starting switch and its respective relay means, a disconnect relay connected to be energized when said respective relay means moves from said off to said on position, said disconnect switch arranged to be closed when said disconnect relay isde-energized, and vice versa, and holdingmeans connected vto holdsaid disconnect relay energized after initial energization thereof until its associated function switch is moved from its on position.

13. lna remote control system for controlling a device having a plurality of movable control members, wherein a remote radio transmitter having a given number of fixed modulation channels transmits modulated control signals to a receiver and selector located in said device for filtering and applying said signals to control circuits'connected to operate saidcontrol members, means for individually controlling more control circuits than available channels, which comprises transfer means'connected to be momentarily energized by a signal in a first one-offsaid channels, afirst group of said control circuits connected respectively to the'outputs of the remainder of said channels by said transfer means when said transfer means is de-energized, a second group of saidcontrol circuits connected respectively to the outputs of said-remainder of channels by said transfer means wheny said` transfer means is energized, a separate pulse producinganeansformomentarily energizing each of said control 22 circuits individually,` a firstgroup of said pulse producing means eachrespectivelyconn'ected to produce pulses'in only one of said remainder of modulation channels, when operated, and a second group Yof said pulse producing means comprising a plurality of ori-off, two-position elec-l trical function switches, relay means associated with eachr of said function switches, means for supplying electrical power to said relay means, each relay means connected in, series with said power supply means and its associated function switch, to be operated from a first relay position to a second relay position whenv its associated function switch is moved from off to on and when said power s upply means is operatively connected, and vice versa, channel selecting means cooperating with each of said relay means and connected to select, but not to energize, a first corresponding one of said remainder of channels whenits associated relay means is in said first relay position andiconnected to select, but not to energize, a second corresponding one of said remainder of channels when said relay means is in said second relay position, and timing means operatively connected by each of said relay means,A when operated from said first to said second relay position, to transmit a transfer pulse in said first channel and to trans,- mit a function pulse, in said second selected channe1, fall ing within the width of said transfer pulse, said timing means also operatively connected by each of said relay means, when operated from said second to said first relay position, to transmit said transfer pulse in said first channel and to transmit said function pulse, in said first selected channel, falling within the widtlr of said transfer pulse, said timing means being adapted and arranged to cause transmission of only one transfer pulse Yand onek function pulse when any function switch is moved from off to on, and vice versa. K

14. Apparatus in accordance with claim 13 wherein said timing means comprises, ateach of said relay means, a first capacitor connected in a charging position when its respective relay means is in its first relay'position, a second capacitor connected in a chargingposition-when said respective relay means is in its second relay position, a dischargingrelay having a coilpermanently wired at4 one end thereof to one end of each ofsaid capacitors, said first capacitor being switched from its charging position to a position connected across-said discharging relay coil when said relay means is moved from said first to said second relay position, said second capacitor being switched from its charging position to a position' connected across said discharging relay coil when said relay means is moved from said second to said first relay position, a pair of transfer contacts operated by said dis-l charging relay and connected in an energizing circuit for said first channel, said transfer contacts arranged tol energize said first channel while said discharge relay coil is carrying discharge current from either of said capacitors, a parir of function contacts operated by said discharging relay, said function contacts arranged to cause completion of an energizing circuit for the particular channel selected by said channel selecting means whenv said discharging relay coil is carrying said discharge current, whereby operation of oneof said function( switches from off to on causes transmission'of said transfer pulse and a function pulsein the corresponding one of said second selected channels, as recited, and whereby operation of the same function switch from on to off causes transmission of saidtransfer pulse and a function pulse in the corresponding one of said first selected channels, as recited.

l5. Apparatus in accordance ywith claim 13A wherein said timing means comprises, at each of said relay means, a first capacitor connected in a charging position when its respective relayv means is in its first relay position', a second capacitor connected in'a charging position' when said respective relay means is in its second relay position, a discharging relay having a coil permanentlyl vwired at one end thereof to one end of each of said capacitors, said first capacitor being switched from its charging position to a position connected across said discharging relay coil when said relay means is moved from said first to said second relay position, said second capacitor being switched from its charging position to a position connected across said discharging relay coil when said relay means is moved from said second to said first relay position, a pair of transfer contacts operated by said discharging relay and connected in an energizing circuit for said first channel, said transfer contacts arranged to energize said first channel while said discharge relay coil is carrying discharge current from either of said capacitors, a pair of function contacts operated by said discharging relay, said function contacts arranged to cause completion of an energizing circuit for the particular channel selected by said channel selecting means when said discharging relay coil is carrying said discharge current, whereby operation of one of said function switches from off to on causes transmission of said transfer pulse and a function pulse in the corresponding one of said second selected'channels, as recited, and whereby operation of the same function switch from on to off causes transmission of said transfer pulse and a function pulse in the corresponding one of said first selected channels, as recited, wherein the energizing circuits for said selected channels contain delay means operating to delay the energization of each of said selected channels for a predetermined interval after its respective function contacts reach their energizing position, and wherein the energizing circuit for said first channel includes holding means operating to delay the de-energization of said first channel for a predetermined time interval after said transfer contacts reach their deenergizing position.

16. Apparatus 1n accordance with claim 13 wherein said power supply means includes a cam-operated start-Y ing switch continuously opened and closed at a constant frequency, the closed interval thereof being a relatively small fraction of the period, and wherein said timing means comprises a cam-operated holding switch continuously opened and closed at said constant frequency, its closed interval starting during the closed interval of said starting switch and continuing for a relatively high percentage of said period, a cam-operated signal switch continuously opened and closed at said constant frequency, its closed interval starting and ending during the closed interval of said holding switch, a first pair of holding contacts at each of said relay means, said holding contacts connected to said holding switch and respectively operated by their associated Yrelay means when reaching said first position to hold said associated relay means in said first position until said holding switch opens, a second pair of holding contacts at each of said relay means, said second pairs also connected to said holding switch and respectively operated by their associated relay means when reaching said second position to hold said associated relay means in said second position until said holding switch opens, transfer contacts at each of said relay means, said transfer contacts connected in an energizing circuit for said first channel and operated by their respective relay means to energize said first channel while said respective relay means is in either of said positions, each of said channel selecting means comprising a first pairV of selecting contacts arranged to be closed while their respective relay means is in said first position and a second pair of selecting contacts arranged to be closed while said respective relay means is in said second position, said selecting contacts connected respectively in corresponding energizing circuits for said first and second selected channels, said energizing circuitsconnected in parallel with said signal switch, and power supply disconnecting means operating at each of said relay means in response to movement of its respective relay means to either of sa-id positions to disconnect said power supply means from that relay 24 means until its associated function switch is moved from its existing position. Y

17. Apparatus in accordance with claim 16 wherein each of said power supply disconnecting means cornprises a disconnect switch connected in series with said starting switch and its respective relay means, a disconnect relay connected to be energized when said respective relay means moves to either of said positions, said Ydisconnect switch arranged to be open when said disconnect relay is energized, and vice versa, and holding means connected to hold said disconnect relay energized after initial energization thereof until its associated function switch is moved from its existing position.

18. Apparatus in accordance with claim 13 wherein each of said relay means comprises a first multiple-pole control relay connected to be energized when its associated function switch is moved from off to on and when said power supply means is operatively connected, and a second multiple-pole control relay connected to be energized when said associated function switch is moved from on to olf and when said power supply means is operatively connected, wherein said power supply means includes a cam-operated starting switch continuously opened and closed at a constant frequency, the closed interval thereof being a relatively small fraction of the period, and wherein said timing means comprises a camoperated holding switch continuously opened and closed at said constant frequency, its closed interval starting during the closed interval of said starting switch and continuing for a relatively high percentage of said pe riod, a cam-operated signal switch continuously opened and closed at said constant frequency, its closed interval starting and ending during the closed interval of said holding switch, a first pair of holding contacts at each of said first control relays, said first pairs connected to said holding switch and respectively operated by their associated first control relays when initially energized to hold said associated first control relay energized until said holding switch opens, a second pair of holding contacts lat each of said second control relays, said second pairs also connected to said holding switch and respectively operated by their associated second control relays when initially energized to hold said associated second control relay energized until said holding switch opens, a pair of transfer contacts operated by each of said control relays, both transfer pairs connected in an energizing circuit for said first channel and arranged to energize said first channel while either of their respective control relays is energized, each of said channel selecting means comprising a first pair of selecting contacts at each of said first control relays, said first pairs of selecting contacts respectively arranged to be closed while their associated first control relay is energized and a second pair of selecting contacts at each of said second control relays, said second pairs of selecting contacts respectively arranged to be closed while their associated second control relay is energized, said selecting contacts connected respectively in corresponding energizing circuits for said first andvsecond selected channels, said energizing circuits connected in parallel with said signal switch, and power supply disconnecting means operating at each of said relay means in response to energization of either of said control relays thereof, to disconnect said power supply means from both those control relays until their associated function switch is moved from its existing position. t

19. Apparatus in accordance withV claim 18 wherein each 'of said power supply disconnecting means comprises a disconnect switch connected in series with said starting switch and a junction of the corresponding two control relays, a disconnect relay connected to be energized when either of said corresponding control relays is energized, said disconnect switch arranged to be open when said disconnect relay is energized, and vice versa, and holding means connected to hold said disconnect relay 25 energized after initial energization thereof until its` associated function switch is moved from its existingr position.

20. A remote radio control system for controlling the flight operations of an aircraft having a plurality of'movable. control members, comprisingA a radio transmitter having a given number of modulators each adapted to produce a different, predetermined modulation frequency on a carrier wave of said transmitter when operatively connected therewith, a receiver associated with said aircraft and having a demodulator, a given number of selective filters, equal in number to said modulators, connected to said demodulator and individually tuned to pass each of said modulation frequencies, respectively, a filter output circuit connected to each of said filters to be energized only while its corresponding modulation frequency is being transmitted, transfer means connected in a rst one of said filter output circuits to be actuated only while a first one of said modulators is operatively connected with said transmitter, a plurality of electrical control circuits connected to operate said control members, said control circuit plurality being substantially greater than said given number of modulators, a first group of said control circuits connected respectively to the remainder of said filter output circuits by said transfer means when said transfer means is non-actuated, and a second group of said control circuits connected respectively to said remainder of filter output circuits by said transfer means when said transfer means is actuated, and a plurality of manually operable, electrical signal producing elements remotely provided at said transmitter, a first group of said signal producing elements each arranged to operatively connect a different one of the remainder of said modulators, respectively, into said transmitter, when operated, and a second group of said signal producing elements each arranged to per atively connect said first modulator into said transmitter for a predetermined length of time only, when operated, and each of said second group of signal producing elements also arranged to operatively connect one of said remainder of modulators, respectively, into said transmitter for a period of time falling within said predetermined length of time, whereby operation of one of said first group of signal producing elements causes energization of a corresponding one of said first group of control circuits and whereby operation of one of said second group of signal producing elements causes energization of a corresponding one of said second group of control circuits.

2l. Apparatus in accordance with claim 20 wherein each of said second group of signal producing elements comprises an on-off switch having means for completing an electrical circuit, and including automatically timed actuating means connected to operate in response to completi'on of each of said electrical circuits, each of said actuating means comprising means for operatively con necting said first modulator into said transmitter to actuate said transfer means, means for operatively connecting one of said remainder of modulators into said transmitter while said transfer means is still actuated, means for effectively disconnecting the one of said remainder of modulators after a predetermined time interval and while said transfer means is still actuated, means for eectively disconnecting said first modulator after a second predetermined time interval, to make said transfer means nonactuated, and means for locking and unlocking said first group of signal producing elements simultaneously with the connecting and disconnecting, respectively, of said first modulator.

22. Apparatus in accordance with claim wherein said second group of signal producing elements includes at least one two-position switch having means for completing two electrical circuits, one in each position, and including first automatically timed actuating means connected to operate in response to completion of one of said circuits,

said'firsti actuating; means comprising means fort opfjet atively connecting said first modulator into said trans.- mitter to actuate said transfer means, meansifor opera tively connecting a corresponding one of said remainder of modulators into said transmitter while' said transfer means is still actuated, means forV effectively disconnecting the one of said remainder of modulators after a first predetermined time interva'l'and while said transfer 'means is still actuated, and means for effectively disconnecting said first modulator after a second predetermined time interval, to make said transfer means non-actuated, and second automatically timed actuating means connected to operate in response to completion of the other of said circuits, said second actuating means comprising means for operatively connecting said first modulator into said transmitter to actuate said transfer means, means for operatively connecting a corresponding second one of said remainder of modulators into said transmitter while said transfer means is still actuated, means for effectively disconnecting the second one of said remainder of modulators after said first time interval and while said transfer means is still actuated, and means for effectively disconnecting said tirst modulator after said second time interval, whereby operation of said two-position switch to one position causes energization of a corresponding one of said second group of control circuits, and whereby operation of said two-position switch to the other position causes energization of a corresponding second one lof said second group of control circuits.

23. Apparatus in accordance with claim 2O wherein said rst group of signal producing elements includes a first ori-off switch causing a current fliow, while on, in its corresponding one of said first group of control circuits, rotary stepping control means in said corresponding control circuit connected to be shifted one increment in a certain direction for each on-off operation of said first switch, and wherein said second group o-f signal producing elements includes a second ori-off switch, the arrangement of said second switch being such that its operation comprises movement of said second switch from one position to the other, only, and two-way latching relay means in the corresponding one of said second group of control circuits connected to be actuated from one relay position to the other in response to said switch movement.

24. Apparatus in accordance with claim 20 wherein each yof said second group of signal producing elements comprises an on-off switch having means for completing an electrical circuit, and including `automatically timed actuating means connected to operate in response to completion of each of said electrical circuits, each of said actuating means comprising means for operatively connecting said first modulator into said transmitter to actuate said transfer means, means for operatively connecting one of said remainder of modulators into said transmitter while said transfer means is still actuated, means for effectively disconnecting the one lof said remainder of modulators after a predetermined time interval and while said transfer means is still actuated, and means for effectively disconnecting said first modulator after a second predetermined time interval, to make said transfer means non-actuated.

25. Apparatus in accordance with claim 24 wherein said first group of signal producing elements includes an additional on-off switch connected to produce a current flow, while on, in its corresponding one of said first group of control circuits, rotary stepping means in said corresponding control circuit connected to be shifted one increment in a certain direction for each on-oft` operation of said additional switch, wherein for at least one of first said on-off switches, said electrical circuit completion comprises movement of said one on-off switch from one position to the other, only, and two-way latching relay means in the corresponding one of said second group of control circuits connected to be actuated from one relay position to the other in response to the connection 

